1. Field of the Invention
The present invention relates to a thrust-reversing rear exhaust structure of a turbojet engine, especially a twin-structure, variable-cycle bypass engine to propel a civilian supersonic airplane.
2. Description of the Related Art
In gas-jet exhaust assemblies as that of the present invention, a primary nozzle of variable cross-section is fitted with several flaps and situated downstream of a primary duct. A primary gas flow is exhausted from the primary nozzle during operation of the engine. A secondary nozzle of variable cross-section is also fitted with several flaps and situated downstream of a secondary duct enclosing the primary duct. The secondary duct extends rearward beyond the exhaust orifice of the primary duct. A secondary gas flow is exhausted from the secondary nozzle during operation of the engine.
A fairing encloses the secondary duct. The fairing is fitted with a throat, the so-called pickup throat, downstream of the exhaust orifice of the secondary nozzle. The throat is followed by a diverging portion.
A thrust reverser is provided comprising two identical eyelids which are pivotable on the fairing on either side of an axial plane of symmetry. The eyelids are able to assume either an active position, namely thrust-reversal, wherein they transversely project into the gas jet downstream of the fairing in order to deflect the gas jet forwardly, or an inactive position, namely forward-thrust, wherein they are situated in the extension of the fairing.
The assemblies also include means for driving the flaps of the primary and secondary nozzles and means for driving the eyelids.
Such an exhaust assembly uses the thrust-reverser eyelids in a manner known per se and which is utilized in the civilian Concorde plane. The eyelids are each pivotably mounted about a transverse axis near an axial plane of symmetry to allow control of the engine's exhaust cross-section as a function of flight modes. The width of the slit separating the upstream end of each eyelid from the downstream end of the fairing is a function of the pivot angle of the eyelids, the angle varying with the flight modes. An air flow issuing from the end of the fairing enters this slit and mixes with the gas flows.